Punnagai means Smile. Smile which has many emotions and represents many gestures and expressions of life. Punnagai is a story of five friends Satya(Gemini Ganesan), Rajan(Muthuraman), Haniff who studied in the same college, while graduating they took an oath in front of Gandhi's statue saying they will always stand with truth. But later they got split as Haniff dies in a car accident and each of them got settled in their profession where they have to cheat their profession and principles. The story begins with three different stories (plots) where as the one friend (Nagesh)out of four explains the story. Will they follow Gandhi's principles ?